1. Field of the Invention
The field of the present invention is spectral filters, and particularly to those spectral filters that employ birefringence to generate an optical path difference in incident light.
2. Background
A hyper-spectral sensor is disclosed in U.S. Pat. No. 6,580,509 to Hutchin, the disclosure of which is incorporated herein by reference. This hyper-spectral filter, while effective in separating bands of light, can be too bulky and heavy for certain applications. Other hyper-spectral sensors generally suffer from the same shortcoming.